Poolside Chat Episode #36: Is there a Minimum Filter Pressure (PSI)?

Poolside Chat Episode 36: Minimum Swimming Pool Filter Pressure

Matthew Simmons

October 23, 2024

2 Minute Read

This is Poolside Chat where every week we answer your questions on how to fix and maintain your swimming pool. Poolside Chat is presented by INYOPools.com, helping pool owners find the right parts since 2001. In today’s episode of Poolside Chat, Rob and Matt tackle another common swimming pool question:

Do pool filters have a minimum pressure rating?

Now here’s your hosts – Matt and Rob.

For optimal performance, I was advised that I should run my variable speed pump at a flow rate high enough to maintain 15 PSI at the DE filter. Do you agree with this advice?

-From Inyo’s Forum

No, we do not agree with his advice. The manufacturer doesn’t list a minimum flow rate or PSI rating, reason being the filters work better with a lower flow rate. On the other hand, if the flow rate is too high, debris could bypass the filter or damage the filter.

If you want to go with an analogy, which I always like to do, you could bring it back to I Love Lucy. Remember the conveyor belt with the chocolates? Well, it was working fine when it was going nice and slow; maybe that is 15 to 20 gallons a minute for your filter.

Everything is working fine, and your filter is feeling great. But then you chuck it up to 50 or 80 gallons per minute, and things just started going haywire. The filter doesn’t have enough time to pick the dirt and it can damage the filter media because pressure is way too high.

But there are times when you do have to kick the flow rate up a little bit. That’s when you are going to backwash or recharge the DE filter. Or, if you vacuum or have to run water features, like a bubbler or waterfall, something like that.

Thank you for joining us and if you have any questions, feel to explore our Inyo forum or our blog. Thank you for joining us. Bye.

Troubleshooting Topics

Controls / Automation

Chlorinators

Skimmers / Drains

Need Replacement Parts?

Swimming Pool Products

9 responses to “Poolside Chat Episode #36: Is there a Minimum Filter Pressure (PSI)?”

Lora

August 10, 2016

mine runs around 18, how do I get it to lower?

Reply
1. Matthew Simmons
  
  August 10, 2016
  
  Is that your normal PSI reading? If it is then, there is not much you can do about it. But if this is a recent occurrence you can try backwashing or cleaning the cartridges to clear debris from the filter.
  
  Reply
Don D

August 11, 2016

How do you change the flow rate? I have a sand filter. It’s at 15psi. When it drops down to 10psi I have to clean the pump basket.

Reply
1. Freddy
  
  August 11, 2016
  
  Fit a smaller pump…this will reduce the flow rate and lower the pressure
  
  Reply
  1. Matthew Simmons
    
    August 12, 2016
    
    Change the motor and impeller to a smaller horsepower to lower the flowrate, it would be cheaper than a whole new pump
    
    Reply
Les J

August 24, 2016

So my 4 psi at 30-35 (flow meter) at 1500 rpm on a variable speed pump is okay? Pool store keeps telling me I need to run it faster. (My inline chlorinator doesn’t seem to use much of its charge-despite switching to 1″tablets.) Entire pool is new. Giant Pentair sand filter (the biggest one model escapes me), Pentair in-line chlorinator.

Reply
1. Matthew Simmons
  
  August 24, 2016
  
  If your water is clear, leave the settings as is; I prescribe to the saying “if it ain’t broke don’t fix it.”
  
  Reply
benjamin

August 25, 2016

I have D.E filter 38 sq. 60 lbs pressure gage reads 4lbs , my hose vacuum cleaner works fine. auto cleaner leisure vac will not move

Reply
1. Matthew Simmons
  
  August 26, 2016
  
  Is this pump motor a single, dual or variable speed? What model is the automatic pool cleaner? When you try to run the automatic cleaner does air enter your system?
  
  Reply